Pete KE9OA wrote:

Hi Michael,
I was in the Synthesizer Group, so I didn't have my hand
in those projects that you mentioned.
Pretty cool, on those microwave parts that you have on hand.
I used to find those kinds of cool things when I visited the Rockwell
Inventory Disposal store. I need to get out there again...............

Pete

I started repairing the Collins/Rockwell receivers in self defense.
They decided that we had to rent a loaner from them, or they wouldn't
repair our equipment. They charged $150/month rent, and took over six
months to fix a receiver. The typical bill was over $1200. I had the
manual, so I popped one open and found the first LO was fried. Rockwell
told me the microwave transistor was 1500, minimum ordered of 18 parts
because it was out of stock. The transistor was a die mounted to a gold
stud, and covered with a drop of epoxy, and no part number. New
Microdyne LPR receivers were right at $1000, and worked a lot better so
I told them to forget it, that we were going to repair what we could,
and replace them with the LPR units, when we had to. I fixed most of
them in under one hour bench time, and less than $20 in parts. The
biggest problem with them was they ran way too hot, and over a five year
period, the circuit boards developed a large black spot in the center of
the board as they cooked themselves to death. Still, it was my first
work with solid state microwave equipment.

I found a VCO board for a Microdyne synthesizer in my junk the other
day. They had used the design for years, and it was becoming harder for
the techs to get them to meet the specs. I was asked to work on them for
while and found a number of problems with the design, and parts that
were selected to replace obsolete parts. I learned a lot of tricks to
clean up a PLL circuit fixing a mountain of rejected modules. It was
harder work convincing both design and manufacturing engineering to
correct the problems, than it was to find the problems.



--
We now return you to our normally scheduled programming.

Michael A. Terrell
Central Florida